The present invention pertains generally to the stabilization of optical information recording media. More particularly, this invention relates to a method for stabilizing optical information recording media through the use of a suitable nitrogen containing compound.
The recording medium, of course, is one of the key elements in any optical information storage system. The commercial viability of the recording medium depends upon such technical parameters as the sharpness in recording and playback of the information, i.e., a high signal to noise ratio, and the medium's stability, e.g., the length of time before the onset of degradation of the optical properties. The longer one can delay the onset of degradation, the better chance one has of prolonging the overall useful life of the medium.
Various methods have been utilized in an attempt to prolong the useful life of optical recording media. Two methods of increasing the chemical and mechanical stability of optical recording media have included the use of a protective layer (Japanese Patent Application Laid Open Nos. 57-60542 and 57-66541), and the use of a "sandwich structure". Another method used to increase the useful lifetime of an optical recording medium includes the use of a thermal and/or mechanical barrier layer. U.S. Pat. No. 4,340,655 employs the use of a thermal and mechanical layer for the purpose of protecting the recording layer from defects such as scratches, dirt and fingerprints. Another function of the thermal and mechanical barrier layer is to prevent the material which is vaporized from the recording layer from depositing on the optical system and other components of the recording apparatus.
Stabilizers have also been suggested for use in various layers of the optical recording medium, all directed to extending the useful life of the overall medium. For example, U.S. Pat. Nos. 4,707,431 and 4,614,705 disclose the use of a preservation stabilizer in a monoacrylate or monomethacrylate underlayer as a means of stabilizing said underlayer. Suitable underlayer preservation stabilizers include quaternary ammonium chloride, diethylhydroxamine, a cyclic amide, a nitryl compound, substituted urea, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, various organic acids, and hydroquinone. U.S. Pat. No. 4,707,431 also discloses the use of a triaryl amino compound or a transition metal complex as a recording layer stabilizer.
Because of the potential value of stable optical information recording materials which have long useful lives, the search for techniques, treatments and useful stabilizers to increase the stability and useful life of such media continues.
Accordingly, it is an object of the present invention to provide a simple and commercially viable method for improving the stability of optical information recording media.
It is another object of the present invention to provide a simple and commercially viable process for stabilizing optical information recording media by incorporating a specific nitrogen containing compound into the media.
Yet another object of the present invention is to prepare an optical information storage medium which exhibits a longer useful life and which also exhibits improved performance over time due to a delay in the onset of degradation of the medium's optical properties.
These and other objects, as well as the scope, nature, and utilization of the invention, will be apparent to those skilled in the art from the following description and the appended claims.